This common problem is most often managed by conservative care: Combination of chiropractic, bodywork and the probably the most important thing stabilization exercises. We have moist people start with the powerhouse with an anti- extension bias.
To Evaluate this problem we start with a regular x-ray. Add a stress film which is having someone bend forwards and backwards and taking the x-ray in that position. Then looking for any movement. We also look for signs of stabilization. The body generally lays down calcium in the surrounding tissues to stabilize. We would see this as osteophytes( point extensions to side of bone), end plate sclerosis( ends of bones growing together)
and ligament calcification. This is best seen on a cat scan but can be seen on an MRI or regular x-ray.
References for this article are:
Defining the inherent stability of degenerative spondylolisthesis: a systematic review in https://thejns.org/spine/view/journals/j-neurosurg-spine/23/2/article-p178.xml
Review Article Spondylolysis and spondylolisthesis: A review of the literature in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5990218/